An inhalation study was conducted to investigate the progression and mechanism(s) of carbon disulfide atherosclerosis in C57BL/6 mice. Mice were exposed to either 0, 50, 500 or 800 ppm CS2 by inhalation for 6 hrs/day, 5 days per week for up to 20 weeks. The hypothesis of the study is that C57BL/6 mice on a high fat diet will develop atherosclerosis in a shorter period of time and with a greater severity if they are also exposed to CS2. In addition, the study investigated whether CS2 exposure can exacerbate the effects of high dietary fat on peritoneal macrophage function. Macrophages are thought to play an important role in processing low density lipoproteins and thus in the development of atherosclerotic plaques. Results on macrophage function analysis were presented at the SOT meeting in March 1995 and a preliminary update on the atherosclerosis study were presented to the NTP Board of Scientific Counselors in June 1995.